Body fluids after CO2 inhalation: insight into panic mechanisms?

Blood gases and electrolyte fluctuations were studied in arterial blood, after a single 35% CO2-65% O2 inhalation, which is known to trigger panic attacks in patients with panic disorder. The immediate effect of this maneuver was a brief hypercapnic acidosis followed by a slight alkalotic rebound, with shifts in Ca2+ and K+. The possible effect of these changes on neuronal membrane excitability is discussed, referring to recent experimental findings in panic provocation.